Inter-Kramers Transitions and Spin-Phonon Couplings in a Lanthanide-Based Single-Molecule Magnet

Published

April 6, 2020

Author(s)

Duncan H. Moseley, Shelby E. Stavretis, Zhenhua Zhu, Mei Guo, Craig Brown, Mykhaylo Ozerov, Yongqiang Cheng, Luke L. Daemen, Rachael Richardson, Gary Knight, Komalavalli Thirunavukkuarasu, Anibal J. Ramirez-Cuesta, Jinkui Tang, Zi-Ling Xue

Abstract

Spin-phonon coupling plays a critical role in magnetic relaxation in single-molecule magnets (SMMs) and molecular qubits. Yet, few studies of its nature have been conducted. Phonons here refer to both intermolecular and intramolecular vibrations. In the current work, we show for the first time spin-phonon couplings between Kramers doublets (KDs, from the crystal filed) in the lanthanide-based SMM Er[N(SiMe₃)₂]₃ (1) and its IR-active phonons, which are observed as avoided crossings in magneto-far-IR spectra with coupling constants approximately equal} 3 cm^-1. In one case, the magnetic peak couples to at least two phonon modes. The far-IR spectroscopy shows at least three field-dependent transitions (within the 4I15/2 ground state/manifold) at ) T: M_{J = ±15/2 ±11/2 at 180 cm}u-1^, and M_J=±15/2 ±9/2 at 245 cm^-1. The transition between the ground and first excited KD in 1 is also observed in inelastic neutron scattering (INS) spectroscopy, moving to higher energy with increasing magnetic field. INS also gives complete photon spectra of 1. Computations using the Periodic DFT method provide the energies of all phonon modes, which compare well with the spectra from INS, supporting the assignment of the inter-KD/magnetic transition in the spectra. The current studies unveil and measure the spin-phonon couplings in a typical lanthanide complex and throw light on the origin of the spin-phonon entanglement.

Citation

Inorganic Chemistry

Volume

59

Issue

7

Pub Type

Journals

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Keywords

inelastic neutron scattering, single molecule magnet, Zeeman splitting

Citation

Moseley, D. , Stavretis, S. , Zhu, Z. , Guo, M. , Brown, C. , Ozerov, M. , Cheng, Y. , Daemen, L. , Richardson, R. , Knight, G. , Thirunavukkuarasu, K. , Ramirez-Cuesta, A. , Tang, J. and Xue, Z. (2020), Inter-Kramers Transitions and Spin-Phonon Couplings in a Lanthanide-Based Single-Molecule Magnet, Inorganic Chemistry, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=928225 (Accessed October 18, 2025)